Polymers have been utilized as medical implants for the last 30 years with much success. Some natural and synthetic polymers are known to be biocompatible, indicating their ability to perform with appropriate host response for biomedical applications. These biocompatible polymers, commonly referred to as polymeric biomaterials, are known to have a wide range of applications due to their wide availability, ease of manufacturing, and tunable mechanical and thermal properties. Some of the most common biomaterials include polyethylene (PE), polyurethane (PU), polytetrafluoroethylene (PTFE), polymethylmethacrylate (PMMA), poly (lactic acid) (PLA), and poly (glycolic acid) (PGA), which currently have found uses as biodegradable sutures and fixation screws. While these materials can be fabricated into complex shapes and are available in a wide range of compositions, most tend to have low tensile strength and Young's modulus for applications that require mechanical robustness. Additionally, polymers have similar properties to that of soft tissue, limiting their radiological detectability. Most polymeric materials lack radio-opacity because their elements possess low electron density and low specific gravity. Several steps have been taken to improve radio-opacity of polymers by incorporating heavy-metal fillers as physical mixtures, attaching heavy-metal salts to the polymer backbone via chelation, and by covalently binding radiopaque elements to monomers prior to their polymerization.
Thermally actuated shape memory polymers (SMPs) are a special class of materials that are capable of switching between a primary and a secondary shape upon a heat stimulus. These versatile materials are used for a wide range of applications such as biomaterials, textiles, and automotive. Previously synthesized SMP foams have proven to rapidly occlude aortic aneurysms and the resulting clot is stable up to 90 days. These SMP foams can further be utilized for a neurovascular occlusion device due to their ultra-low density, which allows for the material to be crimped to a small geometry and delivered to the aneurysm via catheter.